This is a proposal to continue a research relationship with the University of Chile (5-R01-NS-03640-07-09) and with the University of Rochester, N.Y., (1-R01-NS-08048-03-05) which began in 1962 with paired NIH grants to the University of Chile and the University of Wisconsin, with which the U. of Rochester later became associated, for the purpose of continuing a stimulating and productive research activity involving research on the central nervous system and an exchange of research personnel. Chileans coming to Wisconsin can participate in a number of different lines of neurobiological research which are supported primarily by Program Project Grant 5-P01-NS-06225 for which a renewal application has been submitted. The areas of research are concerned with electrophysiology of audition, vision, somesthesis and movement, at nearly all levels of the nervous system. Behavioral studies also are being carried out on these various systems. The approach is comparative and methods employed include CNS electrical stimulation, evoked potential and single unit recordings, the use of computers in experimental control, data collection, analyses and simulation. Anatomical studies also are pursued; these include studies of normal and experimental materials with classical cell and fiber stains on normal and degenerating tissue, autoradiographic and electron-microscopic methods. Anatomical studies include special interest in the hypothalamus and brain stem. Wisconsin personnel going to Chile would work cooperatively with Chilean staff on research described in the Chilean application (NS- 03640) with special attention directed to certain Chilean rodents, marsupials, chiropters and the llama.